The invention relates generally to biomedical devices for collecting hair samples useful in analytical testing for exposure to toxins, chemical agents and drugs of abuse.
Increased drug abuse in North America has been associated with criminal activities, health problems, newborn addiction, lost worker productivity and staggeringly high medical costs. Currently of greatest concern are opiates, (heroin, morphine, codeine), cocaine, marijuana, MDMA (Ecstasy), phencyclidine, amphetamine and methamphetamine. Costs of workplace problems associated with use of cannabinoids are so great as to be incalculable. It is estimated that cocaine addiction afflicts at least 1.7M individuals in the United States. In 1996 it was suggested that an estimated 4.9M persons in the United States had used methamphetamine at least once, and a study published in 1994 suggested that 16% of high school seniors had used crystal methamphetamine at least once. Surveys suggest that 200-300 million people worldwide, and 20 million in the United States, use marijuana on a regular basis, making it the most widely used drug behind caffeine, alcohol and nicotine.
Drugs of Abuse: Cannabinoids are now known to be fat-soluble psychoactive compounds that can persist in the body for prolonged periods of time. Chronic use of this compound can give rise to cardiovascular effects (e.g., increased pulse rate, tachycardia); pulmonary effects (e.g., bronchitis, increased incidence of cancer); and neurological effects (e.g., impairment in: motor ability, coordination, short term memory, sensory perception, attention, extraction time, psychosis, psychological addiction, mood alteration, confusion and hallucination).
Binding to dopaminergic receptors in the brain and periphery, cocaine interferes with normal pathways of neural transmission. Cocaine addiction can result in acute psychoses, violent behavior and cardiac failure. Personality and behavioral changes associated with cocaine abuse may include euphoria, paranoia, confusion, depression, anxiety, schizoprenia, hallucinations, aggressiveness, short temper, dulled emotions and/or poor concentration. Cardiovascular changes include constricted blood vessels and increases in heart rate, blood pressure and body temperature. Death from cocaine abuse is becoming more common, i.e., resulting from respiratory arrest, heart rhythm disturbances, convulsions and stroke.
It is estimated that more than 14% of intravenous opiate users are HIV-infected.
Urinalysis: Several existing diagnostic systems are marketed for testing cocaine and opiates in urine, e.g., ONTRAK(trademark) and ON- LINE(trademark) (Roche Diagnostic Systems, Inc.), the ADx(trademark) automated fluorescence polarization immunoassay system (Abbott Laboratories, Inc.) and EZ-SCREEN(trademark) (Environmental Diagnostics). Schilling et al., 1999 and Smith et al., 1997 have reported cross-reactivity and performance testing results. Problems with urine testing for drugs of abuse include at least the following issues: namely, (i) rapid elimination rates and short half-life of many compounds can result in a shortened detection window; (ii) false negatives can result from purposeful adulteration and interference (Mikkelsen et al., 1988); (iii) false positive results from cross-reactions with certain medications; and (iv) possible uncertainty can result from cross-reactive substances, e.g., poppy seeds.
Hair Testing: Baumgartner and coworkers (1979) report analysis of human hair for the presence of drugs of abuse and use of radioimmunoassays for detection of opiates hair extracts collected from suspected heroin abusers. In the two decades since that first published report, a variety of additional hair test applications have been disclosed, i.e., for both illicit and therapeutic drugs. Hair provides a unique toxicological specimen. Advantages of hair testing are several. First and foremost, it is more difficult to evade drug detection with hair analysis than with urinalysis because hair testing greatly expands the time window for drug detection compared with more common biological samples, such as urine and serum, i.e., providing information only on recent drug use on the order of hours to day. In contrast, hair grows at approximately 1.5 inches for each 90 days in adults (Saitoh et al.,1969). Following deposition in hair, drugs can persist for extended periods of time, and thus provide information on chronic exposure which can complement the shorter-term information provided by urinalysis. Hair testing also offers opportunities to assess patterns of drug use over time, e.g., relatively constant usage vs. intermittent usage, and/or relative severity of usage, e.g., heavy, intermediate or light. Despite legal challenges regarding constitutionality and admissibility, the results of hair drug testing have been admitted to American courts as scientific evidence in criminal cases, military courts-martial, child custody and adoption cases, and cases involving workplace testing programs.
External Contamination: Probative advantages of hair testing may depend on the ability to distinguish how an analyte has become associated with the sample, in this case, whether it results from external surface contamination of hair, i.e., referred to as xe2x80x9cenvironmental exposurexe2x80x9d, or from internal, i.e., xe2x80x9cphysiologicalxe2x80x9d, incorporation into hair. xe2x80x9cWashabilityxe2x80x9d has been used as one way to assess external contamination. Unfortunately, absolute differences do not appear to exist and variability in different hair sample results is reportedly great (Baumgartner et al., 1996). Variability may result from a variety of intrinsic factors including e.g. differences in the natural porosity of different hairs and/or changes induced by dying (DeLauder et al., 2000). In the laboratory, drugs are commonly extracted from hair samples using organic solvents, acids and bases; in possible combination with, papain and dithiothreitol. Handling of hair samples is tedious with intrinsic potential for contamination of the work surface and laboratory workers. Opportunity also exists for possible inadvertent transfer of hairs between samples.
Sample Integrity: Collection methodology is one key to making an effective determination of drug abuse. To minimize errors from possible mishandling of samples, (as well as attempts at purposeful adulteration), collection devices, test methods and laboratory protocols must all address issues of xe2x80x9csample integrityxe2x80x9d, i.e., maintaining control of a sample from collection through processing to the final report of a positive or negative test result. While controls exist for insuring and minimizing laboratory cross-contamination, it would be highly desirable to have a secure collection vessel for hair which would also maintain sample integrity by serving as an extraction vessel for drugs and other analytes.
On-Site Testing: While employers wishing to reduce risks in the workplace may currently submit hair samples for laboratory testing, these programs are expensive, i.e., requiring trained personnel and impeccable record keeping to limit legal liability. In the United States, more than 80% of workers are employed by small and medium-sized businesses. To date, it has been difficult to service the needs of these employers with hair testing methodology. It would be highly desirable to have devices capable of assuring sample integrity through the process from collection of a hair sample, while also allowing collection in a relatively non-obtrusive secure manner by ordinary factory, jail, and school personnel.
The Hair Test Sample: The absolute amount of drug which is incorporated into an individual hair is so low as to preclude detection by current quantitative analytical technologies; consequently, the collection of multiple hairs is necessary to effect adequate sensitivity, specificity and precision in a test method. Hair length is also important since the length is directly related to the time over which an individual may have undergone exposure to an agent. Counting and measuring individual hairs is time consuming and imprecise, and offers opportunities for mishandling and loss of sample integrity. It would be highly desirable, particularly for on-site testing, to effect collection of hair samples in a manner that assures routine harvesting of a pre-determined number of hairs.
Objects of the invention provide secure devices for reproducibly collecting homogeneous samples of hair, i.e., containing a pre-determined number of hairs. In other objects the invention provides a device for maintaining sample integrity. In yet other objects, the invention provides a collection device having an extraction vessel wherein analytes of interest may be extracted from hair.
Hair collection devices are disclosed herein which: (i) collect a pre-determined number of individual hairs for use as a test sample; (ii) minimize sample handling; (iii) maximizing control of sample integrity; (iv) serve as an extraction vessel for dissociating analytes from the hairs in the sample; and, (v) deliver the extract containing the analyte into a detection assay or device without manual intervention, pipetting or special handling. The disclosed hair collection devices safely remove hair from a subject with minimal risk to the operator or subject. The devices allow collection of a hair sample in less than about 10 seconds. Incorrect handling and labeling of samples, is minimized through use of (i) an integrated single unit design; (ii) bar-codable disposable plastic and/or metallic sub-components; (iii) an integral plug-in unit design allowing insertion of the extraction vessel portion of the collection device directly into either laboratory test equipment (e.g., GC/MS) or an on-site immunoassay test device. The devices and methods of the invention find a variety of uses in on-site screening and laboratory test procedures designed to identify exposure to harmful/hazardous materials: e.g., biological agents (e.g., biological toxins and warfare agents), organic chemicals (e.g., toxic benzylic compounds), inorganic metallic compounds (e.g., heavy metal toxins), tobacco products, therapeutic drugs, drugs of abuse and the like.